Her hair color changes, and she loses those weird wire things coming out of her head in B2W2. Her blonde hair is replaced with black hair and she has long brades instead of the wire things. Why is this? Is it a different Elesa or something?
In between the events of Black and White and Black 2 and White 2, she confided in Skyla about changing her image.
Elesa is a supermodel. She probably just wanted to change her look a bit. Another example of this is Nessa. She has different outfits as a model as is shown on her League Card.
Source
Hope I helped!